Adjustable sundial



V Sept. 14, 1965 A. M. MOORE ADJUSTABLE SUNDIAL 2, Sheets-Sheet 1 FiledJune 7, 1963 INVEN TOR. aim? M. Moore ATTORNEY Sept. 14, 1965 A. M.MOORE ADJUSTABLE SUNDIAL Filed June 7, 1963 2 Sheets-Sheet 2 INVENTOR.

47m .M. Moore BY Q ATTORNEY United States Patent 3,205,581 ADJUSTABLESUNDIAL Ann M. Moore, Box 331, Granite Falls, N.C. Filed June 7, 1963,Ser. No. 286,409 1 Claim. '(Cl. 33-62) This invention relates tosundials, and is more particularly concerned with a portable decorativesundial that is adjustable to indicate the sun time in any latitude.

In the past, sundials have taken many forms. Some sundials have beenmade adjustable; but, these previous adjustable sundials have requiredmany metal parts, making the sundial expensive and unattractive.

The sundial of the present invention comprises a face plate having adial thereon. The face plate is pivotally connected to a mounting plateso that the angular disposition of the face plate with respect to themounting plate can be varied.

A gnomon is supported by the face plate. The gnomon is in the form of arod, and is slidably supported at one edge of the face plate and held byslidable means at the opposite edge 'of the face plate.

The present sundial therefore provides a dial that can be mounted andadjusted to face in the proper direction. The gnomon can be adjusted toindicate the sun time in any given latitude. The sundial is readilyadaptable to be a wall dial, horizontal dial, or a dial disposed at anyother angle.

These and other features and advantages of the present invention willbecome apparent from consideration of the following specification whentaken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of one preferred embodiment of the presentinvention;

FIG. 2 is a side elevational view of the device shown in FIG. 1;

FIG. 3 is a top plan view;

FIG. 4 is a detail cross-sectional view of one of the gnomon supports;and,

FIG. 5 is a detail cross-sectional view of the other gnomon support.

In mounting a sundial to indicate sun time, the first principle is tofix the shadow-casting device, or gnomon, so that the edge of the gnomonwhich casts the shadow to be read is parallel to the axis of the earth.The dial on which the shadow is to be read must then be marked withindicia so located as to have the shadow of the gnomon fall across theproper indicium at the proper time.

Things on the earth are located substantially on a tangent to the earth,and the latitude of a given location gives the location of the tangentpoint with respect to the two poles of the earth. To locate the gnomon,therefore, it is necessary to make the angle of the gnomon equal to theangle of the latitude of the location.

For most practical purposes, if a dial face is to point toward theequator (i.e., face north in the Southern Hemisphere and south in theNorthern Hemisphere) the dial can be substantially circular. A dial canof course be oriented in any way desired, as long as the dial isproperly designed. The dial can be designed according to the known lawsof gnomology; or, in the present day of accurate clocks, the variousindicia can be placed empirically by the location of the shadow when aclock indicates a given time.

While the features of the present sundial allow it to be adapted withease to any orientation, the device here presented is designed to facethe equator, and is adapted to be mounted on a vertical wall, providingwhat is known as a wall dial.

3,205,581 Patented Sept. 14, 1965 ice Referring now to the drawings andto that embodiment here presented by way of illustration, the deviceincludes a face plate 10 having a dial 11 thereon. The dial 11 can beapplied in numerous ways; e.g., it can be painted on, etched, separatepieces can be attached, and numerous other methods can be used.

It is contemplated that the face 13 will be made of a plastic sheet orthe like, with a frame 17 of wood or other convenient material. Withsuch a construction, translucent or transparent material can be used forthe face 13, and the dial can be so mounted that it can be read from therear as well as the front, thus providing a kind of window dial.

The face plate 10 is secured to a mounting plate 12. One vertical edgeof the face plate 10 is attached to the mounting plate 12 by hinges 14so the face plate 10 can be disposed at various angles with respect tothe mounting plate 12. It will be understood that the mounting plate 12may be simply a frame, as here shown, or may be a full plate. A wall, asof a house, may serve as the mounting plate 12, with the hinges 14attached directly to the wall.

The opposite vertical edge of the face plate 10 is provided with anadjustable lock 23. The lock 23 includes a bracket 16 secured to themounting plate 12, and pivotally carrying a rod 15. The face plate 10carries a bracket 18 which slidably receives the rod 15, and has alocking screw 19 to fix the rod 15 to the bracket 16.

Thus, the mounting plate 12 can be attached to a wall, and the faceplate 10 can be rotated about the hinges 14 to face true south (or northin the Southern Hemisphere). The pivotal mounting of the rod 15 allowsit to follow the angular motion of the face plate 10, and the lockingscrew 19 can lock the face plate 10 in any desired position by clampingthe bracket 18 to the rod 15.

A magnetic compass 20 is carried by the lower edge of the face plate 10to show the proper setting of the face plate 10. It will of course berealized that the dial 11 must be oriented according to geographic northrather than magnetic north; however, one must simply have the angle ofdeclination of the particular locality (i.e., the angle betweengeographic north and magnetic north) in order to make the neededcorrection. The compass 20, therefore, simplifies the orientation of thesundial.

At the center 'of the lower edge of the face plate 10, and secured tothe frame 17, there is a support rod 21. The support rod can beconveniently installed by inserting it into a hole in the frame 17 ofthe face plate 10. The support rod 21 is preferably perpendicular toface 13. It can be set at various angles; but, the dial is simplified ifthe angle for the gnomon is a linear relationship.

The support rod 21 slidably carries a support block 22. The supportblock 22 has a longitudinal hole 24 therein to receive the support rod21 and a threaded, transverse hole 25 intersects the hole 24 to receivea locking screw 26. Thus, with the locking screw 26 loose, the supportblock 22 can slide freely along the support rod 21, but the screw 26 canbe tightened to lock the support block 22 in any desired location.

The upper surface of the support block 22 has a recess 28 therein whichreceives the lower end 30 of the gnomon 29. It will be noticed in FIG. 5that the recess 28 provides clearance on both sides of the gnomon 29.This clearance allows the block 22 to be moved along the support rod 21,while the gnomon 29 pivots about its opposite end, without binding inthe recess 28.

The gnomon 29 is made of a round rod. The lower end 30 is rounded toseat properly in the recess 28 regardless of the angle of the gnomon 29with respect to the block 22. The upper end 31 of the gnomon 29 has anenlarged portion 32 to limit the movement of i the gnomon 29.

The upper end 31 of the gnomon 29 is slidably held in an eye 34. Aconventional screw eye is screwed into the top edge of theframe 17 ofthe face plate 10, and is fitted with a grommet 35. The grommet 35 fitstightly around the gnomon 29. The grommet 35 is preferably madeof amaterial having considerable deformability and a high coeflicient offriction, such as rubber,

the support block 22 along the support rod 21 until the angle a iscorrect. If desired, indicia may be placed along the rod 21 to indicatethe position of the block 22 to give various angles. g

It is contemplated thatthe dial 11 would. be printed or otherwise placedon the face 13 at the time of manufacture; however, the user can do soif he wishes.

To calibrate the dial 11, the sundial is properly installed as describedabove. The noon mark is normally the first indicium to be placed. Thesimplest method is to note the location of the shadow. ofthe gnomon 29on the face 13 when a clock indicates noon, Once the noon mark isestablished, asimilar procedure is followed to establish the remaininghour, marks from sunrise to sunset. I p p v r During a year, sun timevaries from mean, time, or clock time, the two coinciding only fourtimes during the year. This difference is only 16 minutes at; themaximum, which need not be considered for most purposes in reading asundial. If a high degree of accuracy is desired, a

.1 4 standard chart may be used to show the correction required. 1

It will, of course, be realized that the device here presented is by wayof illustration only, and is meant to be in no way restrictive.Therefore, numerous changes and modifications may be made and the fulluse of equivalents resorted to, without, departing from the spirit orscope of the invention as outlined in the appended claim.

A sundial including a mounting plate adapted to be attachedto a verticalwall, a face plate having oneedge thereof hingedly connected toonevertical edge of said mountingplate, an adjustment rod pivotallyconnected to the oppositetvertical edge of said mounting plate, abracket on .the ,edge of, said face plate adjacent. said opposite.vvertical. edge ,of'said mounting plate, saidbracket slidably receivingvsaid adjustment rod, said. bracket having means for fixingysaid rodwith respectto said bracket, an eye onthe top edge of said face plate,said eye having a grommet therein, a support rod .on the lower edgeofsaid face plate andperpendicular to said face plate, said support rodhaving a support block slidably mounted thereon, a gnornon comprising arod, said gnomon being slidably received through said grommet insaideye, one ,end of said, gnomon being received in a recess in saidsupportblock, and means for fixing said support block with respecttosaid support rod.

' v, References Cited bythe Examiner i UNITED STATES PATENTS1,289,837'12/18' Love 33-62 2,049,034 7/36 Weisz 33-62 2,963,790' 12/60Hall 3362 1 y l UFOREIGN, PATENTS 14,338 3/11 Denmark.

7,283 10/42 France.

587,542 11/33 Germany.

.40 ISAAC LISANN, Primary Examiner.

